This invention relates to an automatic focusing camera. A camera capable of the automatic focusing of the photographic lens, by operation of an electromagnet controlled by an electric signal produced through the detection of the object distance, facilitates photographic work.
Generally, the construction of a camera having a focusing system controlled by an electric signal is inevitably more complicated due to the effect of additional factors, for instance, brightness of the object, when compared with the conventional camera equipped with a coupled range finder with which a photographer adjusts the in-focus position of the photographic lens by observing the coincidence of the double images displayed within the view finder.
In order to detect the in-focus position while taking the effect of those additional factors into consideration, a method is introduced to stop the photographic lens at the in-focus position by means of an electric signal corresponding to the in-focus position during repetition of the scanning operation after the in-focus position has been detected by the first scanning through the whole scanning range with the movable mirror of the conventional range finder directed against the object.
However, since the motion of the movable mirror for the scanning through the whole range is only a little one, the effect of the error in object distance detection between the going and returning scanning motions of the movable mirror is amplified with respect to the determination of the in-focus position of the photographic lense, therefore, the error in scanning cannot be ignored.